Radical Ring Opening Polymerization of Cyclic Ketene Acetals Derived From d-Glucal.

A cyclic ketene acetal (CKA) derived from d-glucal was synthesized, and its polymerization using free radicals has been investigated. NMR analysis of the resulting polymers revealed the formation of polyacetal-polyester copolymers, with up to 78% of ester linkages formed by radical ring-opening polymerization (rROP). Conversely, the polymerization of the monomer-saturated analogue only produced acetal linkages, demonstrating that the alkene functionality within the d-glucal pyranose ring is essential to promote ring-opening and ester formation, likely via the stabilization of an allyl radical.

UV degradation of poly(lactic acid) materials through copolymerisation with a sugar-derived cyclic xanthate.

The copolymerisation of L-Lactide with a cyclic xanthate monomer derived from tri--acetyl-D-glucal has been used to incorporate thionocarbonate and thioester linkages into a polyester backbone. The poly(lactide--xanthate) copolymers show enhanced UV-degradability compared to PLA, with 40% mass loss within 6 hours of UV exposure (365 nm) for only 3% of sulfur-containing linkages.